Life can't get much better than this, I thought, as the Andean farmers' fields spread out beneath me to resemble an organic chessboard and we rode off again in search of the dead.

It was a steep climb and I was beginning to feel sorry for the mule – thoughtfully named Mula – who had been saddled with the unenviable task of lugging my sturdy frame the four and a half kilometres to our goal.

But, as the air grew noticeably thinner and the heat more searing, I was also starting to grow in admiration for the Peruvians who, around 800 years ago and at an altitude of 2,600 metres, had, in the middle of a sheer cliff face, lovingly carved out dwellings for the deceased.

Fortunately for Mula, it was not too long before we had to dismount for a closer view of the Revash tombs. A short scramble up the rocks later and we were among the orange roofs and whitewashed walls that, to European eyes, appeared an oddly homely design for a mausoleum.

As the days went by we would come to understand this architectural choice better, as we continued on a historical tour of northern Peru that was already developing some fascinating, if macabre, themes.

I have not been on too many holidays where spending time in a room full of corpses constitutes a highlight, but, by the time we were examining the lipless grin of a mummified 14-year-old girl in a museum in Leymebamba, the riddle of the curious funereal habits of the region's pre-colonial era had me hooked.

The teenager in question was one of 219 mummies found by anthropologists at the nearby Lake of the Condors eleven years ago and housed in the museum, where we also spent a comfortable, if slightly unsettling night.

Perhaps the most striking thing about the mummies was that they had been found in a foetal position, seemingly evoking the idea of death as a second birth.

This impression was reinforced when we travelled to Karajia to observe a second set of cliff-face tombs, built a few hundred years before those at Revash, by the pre-Inca people known as the Chachapoyas.

Here we made the acquaintance of six huge skittle-like personages, whom the locals, using the Quechua language inherited from the Incas, referred to as the "purun machus" or "old people".

These clay-covered figures, with their geometric visages set to gaze mournfully across the vertigo-inducing valley, housed ancient corpses within their long, smooth bellies in a kind of reverse gestation.

If the erstwhile inhabitants of northern Peru saw death as a kind of mirror image of birth, this seemed to be complimented by a view of the subsequent after-life as having significant parallels with earthly life.

The idea that the hereafter would be markedly similar to the here and now - suggested at Revash by the building of tombs to resemble contemporary homes – seems to have led to a belief that earthly belongings would be useful to the deceased.

The tomb of the so-called Señor or "lord"of Sipán, one of the most celebrated recent archaeological discoveries in Peru, offered a striking illustration of this kind of conviction.

We were able to trawl through much of the startling array of treasure and goods with which the lord was buried at the recently-opened Royal Tombs Museum in Lambayeque.

It is worth noting that the posthumous comfort of this dignitary was considered so crucial that one wife, two concubines, a soldier, a banner bearer, a guard, a 10-year-old boy, two llamas and a dog were killed and buried with him. Many of these tomb-mates were awarded the further distinction of having their feet removed to forestall any cadaverous bid for freedom.

In search of more intellectual fuel for my morbid ruminations on the ancient inhabitants of the northern Andes, I eventually found myself at the mountaintop settlement of Kuelap, frequently mooted as a northern rival to the over-popular Inca site at Macchu Picchu. One of Kuelap's advantages over its southern competitor is that it is older, having been occupied from around 500AD and for at least a thousand years.

Another is the scarcity of tourists. We made the dizzying climb into the clouds at 3,000 metres to reach the citadel - once home to some 3,000 people - and found our only company was a solitary corn cob vendor and several llamas who grazed around the limestone walls.

Furthermore, Kuelap proved to be a metaphorical gold mine for would-be students of the mortuary habits of the Andean peoples. Indeed, death appears to have been the key to its existence.

The citadel lies just opposite to Lake Cuychaculla, which the Chachapoya seem to have considered their tribal "pacarina" or source of life.

It was once a common Andean religious belief that the first humans emerged from water after an act of copulation between the sun and the land, and it appears that the Chachapoya thought their ancestors originated from this particular lake.

Kuelap, on the other hand, littered with human bones, appears to have been seen as a place of death, with particularly grisly associations attaching themselves to its enigmatic centrepiece, known as the "tintero", or inkwell.

The tintero – a round structure several metres high – houses a womb-shaped cavity, at the floor of which, in an echo of the death-birth symbolism observed elsewhere, have been found human bones. Archaeologists are investigating whether, in addition to the sacrifices of llamas and beans they have evidence of at the site, human sacrifices may have taken place.

Human sacrifice appears to have been a widespread feature of Peruvian life in ancient times. Sacrifices were made, anthropologists believe, in response to earthly misfortunes such as, in Peru, earthquakes or possible El Niño events. They constituted an attempt, via death, to restore the vitality of a society.

They seem to arise out of a view of the living and the dead as existing in spheres that are, not merely similar, but mutually influencing, perhaps even interchangeable.

The evidence for this kind of belief abounds at Kuelap, to where, it seems, people in surrounding areas used to transfer the bones of their dead relatives for a more auspicious burial, and whose own inhabitants used to keep the remains of their kin beneath the part of their houses where they prepared food.

These are the practices of those who envisage their daily lives and good fortune as being bound up with their relationship with the dead. The old Peruvians, it seemed, were people who felt the presence of their ancestors always around them.

I have to admit, that at times, as I contemplated the mist-licked walls of Kuelap, or wandered in between the giant adobe pyramids at Túcume, I could sympathise.

Pondering this odd feeling, I initially thought it might be a symptom of the magnificence of the Peruvian landscape, which tempts a person into feeling they are in touch with the eternal. Perhaps, the constantly transforming vistas and weather upset one's sense of time. Maybe I'd just spent too much time hanging around corpses._______________________________________

For more information on PromPeru, visit peru.info. Information regarding Ian's trip can also be found at inkanatura.com

Journey Latin America offers a wide variety of tailor-made and escorted group tours in northern Peru and throughout Latin America. A seven-night tailor-made trip - starting and ending in Chiclayo and visiting Chachapoyas, Gocta Falls, Estancia el Chillo, Revash, Leymebamba, Kuelap and Karajia - costs from £712 per person, based on two sharing. Extending this to a longer 10-day package including domestic flights from Lima and accommodation in Peru's capital, as well as international flights from the UK, starts from £1582. journeylatinamerica.co.uk; +44 (0)20 8747 8315